1. Technical Field of the Invention
The present invention relates to electrical wire connectors that may be rotatingly applied with the aid of handheld tools to electrically connect, cover and bind exposed electrical wire ends; and particularly to electrical wire connectors that may be rotatingly applied with screwdriver tips.
2. Background Art
A screwdriver tip is a longitudinal projection or male structure at the end of a tool, shank, or bit, that is configured with a keyed pattern. Commonly used patterns include straight blade tips for slotted screw heads, Philips tips with their characteristic X pattern and tapered tip, hexagonal head tips, star tips, and square tips. The screwdriver tip is intended to be readily inserted into a closely conforming recess or female fitment on a subject device such as an externally threaded screw type fastener, for the immediate and temporary purpose of installing or otherwise operating or engaging the device by rotation.
The engagement of the tip with the conforming recess or fitment, with the tip being supported with proper alignment relative to the subject device, results in a non-rotational relationship between the tip and the subject device. Applying a rotating force on the tool, shank or bit, that is in excess of the resistance offered by or through the subject device, causes the subject device to be rotated, up to the structural limits of the materials and design.
It is common for externally threaded screw fasteners, such as common wood screws, to have a female structure for receiving a screwdriver tip, or for bolts and machine screws capable of accepting more torque, to have hex head male structure. It is likewise common and practical for internally threaded fasteners to be configured with an external or male type interfacing structure for use with a socket or female type tool tip such as a wrench end. The common hex nut, as is applied to the threaded shank of a bolt, comes quickly to mind as an easy example.
Electrical circuits commonly installed in residential and commercial buildings for lighting and power for plug-in appliances typically use single or multiple strand electrical wires encased in an insulating jacket and bundled two or more together inside sheathing or conduit. Romex.TM. or equivalent wire products are used for running circuits from main fuse panels, connecting between junction boxes, switch boxes and terminal outlet boxes of all types.
For connections in circuits carrying in the range of 30 amperes and 120 or 240 volts, incoming wire bundles are inserted into and clamped to the box, the bundle sheathing within the box is removed to separate the individual conductors, and a short section of the insulating jacket is removed from each wire, exposing a short length of each individual conductor. The conductor ends common to one circuit are joined with a twisting motion. The twisted conductor ends are then secured with electrical wire connectors; internally threaded fasteners capped at one end, made from electrically non-conducting materials.
The prior art of wire connectors used for this type of work include those based on a simple plastic socket with a knurled exterior for easy gripping and turning with the thumb and forefinger, and an internal spiral locking spring. The connector is rotationally threaded over the wire ends and tightened sufficiently finger tight to assure a reliable physical and electrical connection of the wire ends. The skirt of the insulator socket, when properly applied, extends beyond the bared ends and over the insulation. The newly joined wires are then coiled and compressed into the box for closure. Ideal WIRE NUT.TM. is a commonly known brand name for wire connectors of this type.
Variations of wire connectors include interior changes intended to improve the physical and electrical gripping of the wire ends, and exterior appendages and variations intended to facilitate the ergonomics and effectiveness of by-hand application. Related variants to these wire connectors include those applied by machines in manufacturing environments. A representative sampling follows.
Allison's U.S. Pat. No. 4,065,637 is an electrical connector with an external grove formed in the tube to provide a convenient means for holding the tube in an automatic assembly machine. Scott's U.S. Pat. No. 4,227,040 is a screw-on electrical connector disclosing new internal elements, but not suggesting any improvements to the exterior. Blaha's U.S. Pat. No. 4,707,567 is a screw-on electrical connector and method of making it, disclosing internal elements and methods not relating to the exterior. Van Naarden's U.S. Pat. No. 4,858,312 relates to torque control for an automatic connector assembly tool, illustrating a motor driven applicator for installing twist-on wire connectors.
Munniksma's U.S. Pat. No. 5,256,962 is a lighted wire connector. Whitehead's U.S. Pat. No. 5,557,069 is a twist-on connector with special internal and external features intended to improve by-hand application. Whitehead's U.S. Pat. No. 5,559,307 is similar to his '069, the same or a closely related design is optimized for hand application. Tamm's U.S. Pat. No. 5,557,070 is an ergonomically correct by-hand twist-on connector.
It is apparent that the art of wire connectors continues in the main to rely on the oldest and most obvious means of applying torque for installation; twist them on by hand. Attempts to provide connectors compatible with the next most obvious means, socket tipped tools, has flopped commercially due to its inconvenience to electricians to have a socket tipped power tool readily available.
Meanwhile, the construction industry has advanced to the point where commercial electricians carry and use battery powered screwdrivers, or screwguns as they may be called, on the job as a standard tool of the trade. In normal use, the screwguns are virtually always equipped with a Philips tip, the most commonly used fastener geometry in the industry for installing electrical fixtures. However, no where is it apparent in the art that the contemporary use of handheld, battery operated screwguns with the preferred screwdriver tips for installing other electrical apparatus fasteners could be easily and effectively applied to the further purpose of installing wire connectors.